Issn (Print) : 2320 – 3765 issn (Online): 2278 – 8875 I nternational j ournal of a dvanced

II.VECTOR CONTROL 
Vectorcontrol, known as field-oriented control (FOC), is a variable-frequency drive (VFD) control scheme where 
the stator currents of a three-phase AC electric motor are acknowledged as two orthogonal components that can be 
visualized with a vector. One component defines the magnetic flux of the motor, the supplementary is the torque. The 
control system of the drive calculates from the flux and torque references specified by the drive's speed control the 
corresponding current component references. Typically proportional-integral (PI) controllers are employed to keep the 

---

 
ISSN (Print) : 2320 – 3765 
ISSN (Online): 2278 – 8875 
I
nternational 
J
ournal of 
A
dvanced 
R
esearch in
E
lectrical, 
E
lectronics and 
I
nstrumentation 
E
ngineering 
(An ISO 3297: 2007 Certified Organization) 
Vol. 4, Issue 4, April 2015
Copyright to IJAREEIE 10.15662/ijareeie.2015.0404138 2582 
measured current components at their reference values. The pulse-width modulation of the variable-frequency drive 
describes the transistor switching according to the stator voltage references that are the output of the PI current 
controllers.FOC is used to manage the AC synchronous and induction motors. It was originally developed for high-
performance motor applications that are required to operate smoothly over the bursting speed range, generate 
full torque at zero speed, and have high dynamic performance including fast acceleration and deceleration. However, it 
is becoming increasingly attractive for lower performance applications also due to FOC's motor size, cost and power 
consumption reduction dominance. It is expected that with increasing computational power of the microprocessors it 
will ultimately nearly universally relocate single-variable scalar volts-per-Hertz (V/f) control.